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@einen tutes latent @frn W. I3. ROBINSON, OF DETROIT, MICHIGAN.

Letters Patent No.` 61,105, dated January 8, 1.867.

IMPROVEMENT IN STEAM-ENGINE SLIDE-VALVES.

y dillo tlgehitlt nient tu in time Etnias @anni mit matting tutti tige sume.

TO ALL WI-IOM IT MAY OONCERN:

"Bc it known that I, W. B. RBINSON, of Detroit, in the county of Wayne, and-State of Michigan, have invented a new and useful Improvement in Packing-Rings forbalanced Steam-Valves and other purposes and I do hereby declare that the following is a full, clear, and exact description thereof.

This invention consists in so constructing the packing-rings of balance steam-valves, that the bearing surfaces shall be reduced in such a manner that a steam-joint may be much more easily made where the valve is in motion than formerly, and also in making provision for the escape of steam.

To enable others skilled in the art to make and use my invcntion,.I will proceed to describe its construction and operation, reference being had tothe accompanying drawings, forming a part of this specification, and to the letters of reference marked thereon.

Figure 1 represents a plan or top View of the valve and ring and steam-chest with the cover olf.

Figure 2 is a vertical section through the line yy, of fig. 1.

Figure 3 is an enlarged section of iig. I, through the line z e.

Similar lettersof reference indicate like parts.

A represents `the steam-chest; B thev sliding-valve; O C Gthe ports of the engine; E and E the valve-ro attachment; F is the steam-chest cover, against the under side of which the rings rub; G and G are the pack-ing-rings. These rings are similar to the rings used in my valve patented September I5, 1863, and are a modification and improvement on the same. There are objections to those par-.king-rings which I obvia-te in my present improvement, by making them of differential surfaces. I diminish the bearing surfaces, where a joint' is to be made, by the pressure either of steam or springs. For this purpose I make the surface of the anglering G, where it bears against the cover, much less than formerly, and I eut away the ring G at h, about onehalf its thickness, leaving the bearing surfe ce only about one-half of what it formerly was. On the inside surface of the ring G I turn out a recess, o, seen in figs. 2 and 3. This recess reduces the bearing surface of G when it bears against the flange g, about onc-half.' This cavity or recess o has another duty to perform, which I will refer to presently. Spiral springs, S, are placed at suitable distances apart which act against the bottom portion of the angle-ring G, and which keep the rings in place, pressing them against the steam-chest cover. The steam presses at this point and also on the outside of G at z', which pressure keeps the rings steam-tight against the under side of the cover, and also against the ilangcg; the action or effect of the steam pressing upon G at z' being to compress the rings around the flange and make a steam-tightjoint. These rings are cut into segments as usual, so that they readily adapt themselves to the circle or diameter of the ilange. The recess o is designed not only to relieve the inside of the ring G of a portion of the pressure-bearing surface, but to receive any accidental leakage of steam, and to discharge it through holep, through the flange g, into the interior 0r counterbalanced portion of the valve. It has been found in practice that the interior and exterior bearing surfaces of the rings being equal or about equal, steam would sometimes get between thc interior surface and the flange and interfere with the proper action of the packing. The same may be said in reference to the bearing surfaces of the rings against the under side of the cover. The action of the springs was `found to be not always lquick enough, and steam would get between those surfaces, and interfere with thc proper working of the valve. I have discovered that by making the bearing surface only about enc-half of the surface or area acted on by the steam, I obviatc these objections. There are holes, r, in the flange T of the valve to admit the steam to act against the outside of the angle-ring G, as well as on its bottom surface. As my' invention relates particularly to the construction of the packing-rings and the flanges which confine them, I have not deemed it important to show or describe the steam-chest'complete, as the arrangement is readily understood by engineers or those interested. My improvement can be applied withk equal facility and benefit to rectangular surfaces, as angle-bars or packing, strips, and consequently I do not coniine myself to the particular form f packing herein described.

Having thus described my invention, what'I do claim, and desire to secure by Letters Patent, is-

1. Making packing-rings or packing-strips of differential surfaces, 'and with the recess o, substantially as described. A

2. I claim the holes p, through the flange g, in combination with the packing-rings or strips, substantially as set forth.

W. B. ROBINSON. `Witnesses:

' A. W. Rien,

GEO. RoBINsoN. 

